I recently read an article that made the claim that with the help of technology it will be possible to make human beings faster than we ever thought possible, with 100m times under 5 seconds not out of the realm of possibility. According to the article, ” Professor Peter Weyand, Southern Methodist University (Texas), known for his expertise in terrestrial locomotion and human and animal performance, told TOI that humans would soon have the ”ability to modify and greatly enhance muscle fibre strength.” This is crucial as it would actually reduce the difference between the muscle properties of humans and the world’s fastest animal, the cheetah, to almost zero.”

With all due respect, and I blame the article more than the Professor for leaving this out, but it’s not that simple. Certainly increasing muscular strength is the first and arguably most important step to increasing speed but it’s not the only hurdle. It may come as a surprise to some that our strongest and fastest athletes today don’t even use all of their potential strength when they compete. If they could they would but their bodies won’t let them. Due to what’s called autogenic inhibition, in most instances where we exert ourselves near our maximum, the body blocks our ability to utilize all our muscle fibers. In other words, we are only able to use a percentage of our full strength. The reason for this is simple. We are not designed to withstand the forces that our bodies would produce if we could utilize our full strength. In cases were people have been over to override autogenic inhibition, such as when a man lifts a boulder off of himself to save his own life or when a mother lifts a car off her child, people have been known to rupture muscles or even tear tendons right off the bone. Clearly, simply increasing muscle strength is only part of the answer.

If you want to build a faster human, there are a few things you have to do. The first is change the actual composition of the muscle. If your going for pure speed then Type II b muscle fibers are ideal. These produce the greatest amount of force due to, among other reasons, the fact that more fibers are connected to a single motor neuron than with Type II a or Type I fibers. While it is possible to change a small amount (10% at most) of muscle fibers from one type to another through training, we currently have no method for changing the composition of an entire muscle. Next comes strengthening the muscle itself, either through hypertrophy ( making the fibers bigger) or hyperplasia (making more muscle fibers.) Both of these are possible and may only be a few years away due to treatments such as stem cells to build new muscle fibers and myostatin inhibition to increase there size. In addition it is important to increase the strength of the tendons and bones as well, for reasons previously mentioned. I currently know of no method for increasing the strength of tendons and bones other than the old fashion way of resistance training, which I doubt would be sufficient. It may require increasing the density of bones or perhaps even changing their composition to stronger materials, but that is just speculation on my part.

If the challenges are overcome, all of the above will make humans faster, but if you really want to improve speed your going to have to do something drastic. As mentioned elsewhere in the article, ‘‘The fast four-legged runners or quadrupeds do seem to be advantaged versus bipeds in terms of the mechanics allowed by their anatomy. These mechanics help quadrupeds to get the most out of the muscles that they have in a way that bipedal runners probably cannot.” If you want to make humans the fastest animal on earth, we’re going to have to ditch the hands for another pair of feet.